US Fish & Wildlife PublicationsCopyright (c) 2018 University of Nebraska - Lincoln All rights reserved.https://digitalcommons.unl.edu/usfwspubs
Recent documents in US Fish & Wildlife Publicationsen-usFri, 09 Feb 2018 01:45:38 PST3600Developing Burbot Propagation Methods - Aquatic Species Conservationhttps://digitalcommons.unl.edu/usfwspubs/531
https://digitalcommons.unl.edu/usfwspubs/531Wed, 07 Feb 2018 09:26:16 PST
As many native fishes struggle with changes in the Missouri River Ecosystems, Garrison Dam NFH’s role in fisheries conservation has evolved to include the production of native fishes, such as the paddlefish, sturgeon and burbot. To meet production requests for these fish, Garrison Dam NFH has modified the hatchery’s existing infrastructure and developed new techniques in fish culture.

Service Fishery Conservation Offices, with our State and Tribal partners are concerned with downward trends in burbot populations. While the fisheries field offices are evaluating the status of local burbot populations and their habitats and assessing the need for supplemental stocking, Garrison NFH is pioneering methods to spawn and propagate burbot in captivity.

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Rob HolmSeabirds as regional biomonitors of legacy toxicants on an
urbanized coastlinehttps://digitalcommons.unl.edu/usfwspubs/530
https://digitalcommons.unl.edu/usfwspubs/530Wed, 07 Feb 2018 09:26:10 PST
Seabirds are often cited as sentinels of the marine environment, but are rarely used in traditional ocean and coastal contaminant monitoring. Four classes of persistent organic pollutants (POPs, n=68) and three trace elements (mercury, selenium, and arsenic) were measured in the eggs of California least terns (Sterna antillarum browni), caspian terns (Hydroprogne caspia), double-crested cormorants (Phalacrocorax auritus), and western gulls (Larus occidentalis) that nest in the Southern California Bight. Building on a periodic five year regional monitoring program, we measured contaminant exposure and assessed the utility of seabirds as regional contaminant biomonitors. We found that the eggs of larger,more piscivorous species generally had the highest concentrations of POPs and trace elements while California least terns had the lowest concentrations, except for mercury which was higher in least terns. As expected, DDT concentrations were elevated near the Palos Verdes Superfund site. However, we also detected a previously unknown latitudinal pattern in PBDE concentrations in least terns. POP congener profiles also confirmed differences in contamination in urban least tern colonies closest to urban centers. Though toxicants were at detectable levels across species and sites, concentrations were below those known to cause adverse effects in avian taxa and are steady or declining compared to previous studies in this region. Our results suggest that regional seabird monitoring can inform site-specific remediation and support management and protection of regionally-threatened wildlife and coastal systems. Integration of seabird contaminant data with traditional sediment, water, bivalve and fish monitoring is needed to further our understanding of exposure pathways and food web contaminant transfer.
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Corey A. Clatterbuck et al.Incorporating Human Dimensions Objectives Into Waterfowl Habitat Planning and Deliveryhttps://digitalcommons.unl.edu/usfwspubs/529
https://digitalcommons.unl.edu/usfwspubs/529Wed, 07 Feb 2018 09:26:04 PST
The 2012 revision of the North American Waterfowl Management Plan (NAWMP) explicitly recognized the need to increase recruitment and retention of waterfowl hunters, birdwatchers, and other conservationists to maintain support for wetland conservation. The incorporation of human dimensions objectives within the NAWMP has compelled waterfowl and wetland managers to consider whether and to what extent landscape characteristics such as public land access; the type, amount, and location of wetlands; and site infrastructure will increase support for wetland conservation among user groups. Further, it has forced the waterfowl community to consider the possible trade-offs between managing land to achieve biological versus social objectives. We used publicly available, long-term data sets to illustrate a method of incorporating human dimensions into waterfowl habitat planning and management. We used United States Fish and Wildlife Service waterfowl harvest survey data, United States Geological Survey band encounter data, and Cornell Lab of Ornithology eBird data to summarize travel characteristics of wetland bird enthusiasts (i.e., waterfowl hunters and birdwatchers) in the Atlantic Flyway. Greater than 90% of all trips by wetland bird enthusiasts occurred within their state of residence. We used data from New York, USA, to demonstrate how to construct discrete choice recreation demand models to identify factors that influence site selection and participation. We demonstrate how model outputs, such as the expected change in the number and geographic distribution of recreational trips (i.e., hunting or bird watching), can be used as an objective metric to evaluate the benefits of alternative habitat acquisition and restoration projects relative to the human dimensions objective of the NAWMP. These data and methods show promise for incorporating human dimensions objectives into habitat delivery and understanding potential trade-offs relative to biological objectives.
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Patrick K. Devers et al.Sparrow Nest Survival in Relation to Prescribed Fire and Woody Plant Invasion in a Northern Mixed-Grass Prairiehttps://digitalcommons.unl.edu/usfwspubs/528
https://digitalcommons.unl.edu/usfwspubs/528Wed, 07 Feb 2018 09:25:57 PST
Prescribed fire is used to reverse invasion by woody vegetation on grasslands, but managers often are uncertain whether influences of shrub and tree reduction outweigh potential effects of fire on nest survival of grassland birds. During the 2001–2003 breeding seasons, we examined relationships of prescribed fire and woody vegetation to nest survival of clay-colored sparrow (Spizella pallida) and Savannah sparrow (Passerculus sandwichensis) in mixed-grass prairie at Des Lacs National Wildlife Refuge in northwestern North Dakota, USA.We assessed relationships of nest survival to 1) recent fire history, in terms of number of breeding seasons (2, 3, or 4–5) since the last prescribed fire, and 2) prevalence of trees and tall (>1.5 m) shrubs in the landscape and of low (≤1.5 m) shrubs within 5 m of nests. Nest survival of both species exhibited distinct patterns related to age of the nest and day of year, but bore no relationship to fire history. Survival of clay-colored sparrow nests declined as the amount of trees and tall shrubs within 100 m increased, but we found no relationship to suggest nest parasitism by brown-headed cowbirds (Molothrus ater) as an underlying mechanism. We found little evidence linking nest survival of Savannah sparrow to woody vegetation. Our results suggest that fire can be used to restore northern mixed-grass prairies without adversely affecting nest survival of ≥2 widespread passerine species. Survival of nests of clay-colored sparrow may increase when tall woody cover is reduced by fire. Our data lend support to the use of fire for reducing scattered patches of tall woody cover to enhance survival of nests of ≥1 grassland bird species in northern mixed-grass prairies, but further study is needed that incorporates experimental approaches and assessments of shorter term effects of fire on survival of nests of grassland passerines.
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Robert K. Murphy et al.Nationwide Residues of Organochlorine Pesticides in Wings of Mallards and Black Duckshttps://digitalcommons.unl.edu/usfwspubs/527
https://digitalcommons.unl.edu/usfwspubs/527Wed, 07 Feb 2018 09:25:50 PST
Nationwide monitoring of organochlorine pesticides in wings of more than 24,000 mallards and black ducks bagged during the 1965 and 1966 hunting seasons showed DDE to be the predominant residue, followed in order by DDT, DDD, dieldrin, and heptachlor epoxide. Residues were generally highest in wings from the Atlantic and Pacific Flyways, and lowest in the Central Flyway. DDE was reported for every State and was notably high in wings from New Jersey, Massachusetts, Connecticut, Rhode Island, New York, Pennsylvania, Alabama, California, and Utah. Dieldrin residues were prevalent in wings from Arkansas, Texas, Utah, California, and several States in the Atlantic Flyway.
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Robert G. HeathThe utility of point count surveys to predict wildlife interactions with wind energy facilities: An example focused on golden eagleshttps://digitalcommons.unl.edu/usfwspubs/526
https://digitalcommons.unl.edu/usfwspubs/526Wed, 07 Feb 2018 09:25:45 PST
Wind energy development is rapidly expanding in North America, often accompanied by requirements to survey potential facility locations for existing wildlife. Within the USA, golden eagles (Aquila chrysaetos) are among the most high-profile species of birds that are at risk from wind turbines. To minimize golden eagle fatalities in areas proposed for wind development, modified point count surveys are usually conducted to estimate use by these birds. However, it is not always clear what drives variation in the relationship between on-site point count data and actual use by eagles of a wind energy project footprint. We used existing GPS-GSM telemetry data, collected at 15 min intervals from 13 golden eagles in 2012 and 2013, to explore the relationship between point count data and eagle use of an entire project footprint. To do this, we overlaid the telemetry data on hypothetical project footprints and simulated a variety of point count sampling strategies for those footprints. We compared the time an eagle was found in the sample plots with the time it was found in the project footprint using a metric we called “error due to sampling”. Error due to sampling for individual eagles appeared to be influenced by interactions between the size of the project footprint (20, 40, 90 or 180 km2) and the sampling type (random, systematic or stratified) and was greatest on 90 km2 plots. However, use of random sampling resulted in lowest error due to sampling within intermediate sized plots. In addition sampling intensity and sampling frequency both influenced the effectiveness of point count sampling. Although our work focuses on individual eagles (not the eagle populations typically surveyed in the field), our analysis shows both the utility of simulations to identify specific influences on error and also potential improvements to sampling that consider the context specific manner that point counts are laid out on the landscape.
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Maitreyi Sur et al.The Effect of Putrefaction of Eggs Upon Residue Analysis of DDT and Metaboliteshttps://digitalcommons.unl.edu/usfwspubs/525
https://digitalcommons.unl.edu/usfwspubs/525Wed, 07 Feb 2018 09:25:39 PST
In conjunction with environmental pollution studies, it often is necessary to analyze field-collected eggs that are partially decomposed. The effect of putrefaction upon residue analysis, however, is not known and the experiment reported here was designed to determine if recoveries of DDT, DDE, and DDD differed between fresh and addled eggs and also if putrefaction causes appreciable degradation of DDT.
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Bernard M. Mulhern et al.Potential impacts of offshore oil spills on polar bears in the Chukchi Seahttps://digitalcommons.unl.edu/usfwspubs/524
https://digitalcommons.unl.edu/usfwspubs/524Wed, 07 Feb 2018 09:25:33 PST
Sea ice decline is anticipated to increase human access to the Arctic Ocean allowing for offshore oil and gas development in once inaccessible areas. Given the potential negative consequences of an oil spill on marine wildlife populations in the Arctic, it is important to understand the magnitude of impact a large spill could have on wildlife to inform response planning efforts. In this study we simulated oil spills that released 25,000 barrels of oil for 30 days in autumn originating from two sites in the Chukchi Sea (one in Russia and one in the U.S.) and tracked the distribution of oil for 76 days. We then determined the potential impact such a spill might have on polar bears (Ursus maritimus) and their habitat by overlapping spills with maps of polar bear habitat and movement trajectories. Only a small proportion (1 -10%) of high-value polar bear sea ice habitat was directly affected by oil sufficient to impact bears. However, 27-38% of polar bears in the region were potentially exposed to oil. Oil consistently had the highest probability of reaching Wrangel and Herald islands, important areas of denning and summer terrestrial habitat. Oil did not reach polar bears until approximately 3 weeks after the spills. Our study found the potential for significant impacts to polar bears under a worst case discharge scenario, but suggests that there is a window of time where effective containment efforts could minimize exposure to bears. Our study provides a framework for wildlife managers and planners to assess the level of response that would be required to treat exposed wildlife and where spill response equipment might be best stationed. While the size of spill we simulated has a low probability of occurring, it provides an upper limit for planners to consider when crafting response plans.
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Ryan R. Wilson et al.RECOVERY PLAN FOR THE
SALT CREEK TIGER BEETLE
(<i>Cicindela nevadica lincolniana</i>)https://digitalcommons.unl.edu/usfwspubs/523
https://digitalcommons.unl.edu/usfwspubs/523Mon, 17 Apr 2017 12:20:53 PDT
Current Species Status: The Salt Creek tiger beetle (Cicindela [Ellipsoptera] nevadica lincolniana) was listed as a federally endangered subspecies on November 7, 2005 (70 FR 58335, October 6, 2005). On May 6, 2014 (79 FR 26013), we published a revised final rule designating approximately 449 hectares (1,110 acres) of critical habitat for the Salt Creek tiger beetle in Lancaster and Saunders Counties in Nebraska. The Salt Creek tiger beetle has a recovery priority number of 6C, which means it is a subspecies that faces a high level of threat, including conflict with development activities; a priority number of 6C also indicates it has a low potential for recovery. The Salt Creek tiger beetle has one of the most restricted ranges of any insect in the United States and is currently limited to segments of Little Salt Creek and adjacent remnant saline wetlands in northern Lancaster County, Nebraska.

Habitat Requirements and Limiting Factors: The Salt Creek tiger beetle requires open, barren saline mud flats and mud banks of streams with saline seeps for constructing larval burrows, moving to and from dispersal corridors, foraging, and maintaining thermoregulation (ability of an organism to regulate its body temperature using internal and external mechanisms).

The primary threat to this species is loss and degradation of saline wetland and stream habitats due to commercial, residential, and agricultural development. Construction of levees, reservoirs, and additional channelization of Salt Creek resulted in the degradation and loss of saline wetlands and seeps and entrenchment of its associated tributaries (i.e., Rock, Little Salt, Oak, and Haines Branch Creeks). Contamination, artificial lights, invasive plants, floods, and drought can also have a negative impact on this insect. The Salt Creek tiger beetle is currently found on only one stream segment (Little Salt Creek), which makes it subject to high extinction risk should a catastrophic event occur.

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Matt HoganFinal Recovery Plan Available for the Endangered Salt Creek Tiger Beetlehttps://digitalcommons.unl.edu/usfwspubs/522
https://digitalcommons.unl.edu/usfwspubs/522Mon, 17 Apr 2017 12:15:47 PDT
DENVER - The endangered Salt Creek tiger beetle is not only one of the worlds rarest insects but also a voracious predator that pounces like a tiger, using part of its mandibles to capture prey that is as big as it is.

This amazing beetle is only found in the salty muddy banks of the Little Salt Creek near Lincoln, NE. To try to save it from extinction and conserve the habitat it calls home, the U.S. Fish and Wildlife Service (Service) is releasing the Salt Creek Tiger Beetle Final Recovery Plan, which includes identification of important recovery areas in Lancaster and Saunders Counties. The plan guides management of the beetle for the next decade, describes actions necessary for the beetle’s recovery, and establishes criteria for both downlisting (to threatened status) and delisting the species. It also includes the time and cost for implementing the needed recovery actions.

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Coyote space use in relation to prey abundancehttps://digitalcommons.unl.edu/usfwspubs/521
https://digitalcommons.unl.edu/usfwspubs/521Thu, 13 Apr 2017 12:39:46 PDT
Food abundance is an important factor determining space use in many species, but its effect on carnivore home range and territory size has rarely been investigated. We explored the relationship between food abundance for the coyote (Canis latrans) and space use in two study areas in the northern Great Basin, where the primary prey, the black-tailed jackrabbit (Lepuscalifornicus), fluctuates dramatically in abundance. At one site, home ranges and temtories were significantly larger during a time of prey scarcity than when prey was abundant. Coyotes on the second site had similar-size home ranges and territories at low and high prey abundance, but a higher proportion and probably a higher number of individuals were transients during the prey-scarcity period. We propose mortality rates of coyotes as an important factor mediating adjustments in space use to food abundance, and suggest two mechanisms by which mortality might interact with food abundance. Higher mortality rates may simply permit more rapid adjustment of home range size to changing food conditions. Alternatively, higher mortality may selectively eliminate transients, thus reducing the impact of intruders in limiting the size of the remaining territories.
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L. Scott Mills et al.Breakfast at the Cockpit Café and
Other Innovations in Protected Area Outreachhttps://digitalcommons.unl.edu/usfwspubs/520
https://digitalcommons.unl.edu/usfwspubs/520Thu, 13 Apr 2017 12:36:27 PDT
Fundamental changes in protected area outreach and education strategies are dissolving old boundaries and fostering innovative approaches to civic engagement. The practice of community-based ecosystem management as presented by Meffe et al. (2002) provides an organizing framework blending ecological, institutional and sociocultural perspectives. This framework flows from a definition of ecosystem management that considers sustaining ecosystem structure and processes across spatial and temporal scales in tandem with societal priorities. The decision-making authority in this system, envisioned as collaborative and participatory, can present challenges for traditionally trained protected area managers. This definition views ecosystem management as:

. . . an approach to maintaining or restoring the composition, structure, and function of natural and modified ecosystems for the goal of long-term sustainability. It is based on a collaboratively developed vision of desired future conditions that integrates ecological, socioeconomic and institutional perspectives, applied within a geographic framework defined primarily by natural ecological boundaries (Meffe et al. 2002:70, emphasis added).

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Christine Baumann Feurt et al.FROM PROTOZOAN INFECTION IN MONARCH
BUTTERFLIES TO COLONY COLLAPSE DISORDER
IN BEES
Are Emerging Infectious Diseases Proliferating in the Insect World?https://digitalcommons.unl.edu/usfwspubs/519
https://digitalcommons.unl.edu/usfwspubs/519Thu, 13 Apr 2017 12:33:31 PDT
In the late 1990S, scientists first noticed mysterious declines in several wild bumble bee species (Bombus spp.) in both eastern and western North America, with one species now possibly extinct (Colla and Packer 2008). These bumble bee losses mirrored declines in the abundance of many other native pollinators (National Research Council 2007). Interestingly, the timing of bumble bee declines in the United States coincided with reports of disease outbreaks in commercial- reared bumble bees sold for use in the production of greenhouse tomatoes and peppers (Evans et al. 2008). This observation, together with reports of a higher incidence of key pathogens, including the trypanosome Crithidia bambi and the micros poridian Nosema bambi in wild bumble bees foraging near greenhouse colonies (Colla et al. 2006), suggests that the spread of pathogens from commercial to wild bees could play a role in observed declines. Although details are still emerging on the incidence and effects of different bumble bee pathogens in North America, this example could be one of the first cases of pathogen spillover from domestically reared to wild populations of an insect host. More generally, this example points to the potential for pathogens to cause insect declines, and underscores the need for more baseline data on pathogen prevalence in wild insect populations.
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Rebecca Bartel et al.Breeding Birds Of Research Natural Areas In
Southeastern Alaskahttps://digitalcommons.unl.edu/usfwspubs/518
https://digitalcommons.unl.edu/usfwspubs/518Thu, 13 Apr 2017 12:29:01 PDT
The Tongass National Forest encompasses a large expanse of temperate rainforest in southeastern Alaska and contains 12 designated Research Natural Areas (RNAs). Existing in as near a natural condition as possible, RNAs receive minimal commercial and recreational use. Because few bird studies have been conducted on RNAs, we used point counts and area searches to determine the occurrence and abundance of breeding landbirds present in vegetation communities of RNAs. Of 49 species of small landbirds detected during area searches, the most widely distributed birds among RNAs were rufous hummingbird (Selasphorus rufa), chestnutbacked chickadee (Poecile rufescens), winter wren (Troglodytes troglodytes), golden-crowned kinglet (Regulus satrapa), Swainson’s thrush (Catharus ustulatus), hermit thrush (C. guttatus), varied thrush (Ixoreus naevius), and Townsend’s warbler (Dendroica townsendi). The 8 most abundant species recorded on 187 point counts (.0.5 birds/point) were Pacific-slope flycatcher (Empidonaxdifficilis), hermit thrush, varied thrush, winter wren, golden-crowned kinglet, Townsend’s warbler, and chestnut-backed chickadee. Several species had significant differences in abundance between low- elevation hemlock-spruce forest and their abundance in either high- elevation fir-spruce forest or mixed conifer-shore pine muskeg. Because RNAs provide forests that are not disturbed by human activities, these sites could provide a standard to evaluate changes in bird abundance and richness that may occur on developed land in southeastern Alaska.
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Brad A. Andres et al.Fall Trumpeter Swan Survey
of the
High Plains Flock
Fall 2010https://digitalcommons.unl.edu/usfwspubs/517
https://digitalcommons.unl.edu/usfwspubs/517Thu, 03 Mar 2016 09:53:56 PST
The annual fall trumpeter swan survey is conducted to determine production and distribution for a portion of the Interior Population of trumpeter swans called the High Plains Flock, in accordance with the Interior Population and High Plains Flock trumpeter swan management plans (1997 and 2005, respectively). Each plan outlines population objectives (VI-2 and A-1) and management strategies for monitoring population status, which includes aerial surveys in South Dakota and Nebraska. These surveys are part of a trumpeter swan monitoring program that spans over two decades to track abundance trends in the flock and condition of the wetlands swans inhabit.
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Shilo Comeau et al.Long-Billed Curlew (<i>Numenius americanus</i>) Rangewide Survey and Monitoring Guidelineshttps://digitalcommons.unl.edu/usfwspubs/516
https://digitalcommons.unl.edu/usfwspubs/516Thu, 03 Mar 2016 09:53:40 PST
LBCUs are a species of special concern throughout much of their breeding range in North America, with both the U.S. and Canadian Shorebird Plans listing them as “Highly Imperiled” (Brown et al. 2001). LBCUs are also listed in the U.S. as a Bird of Conservation Concern, at the National level, within FWS Regions 1, 2, 4 and 6, and for many Bird Conservation Regions (U.S. Fish and Wildlife Service 2002). This level of concern is due to apparent population declines, particularly in the shortgrass and mixed-grass prairie of the western Great Plains (Brown et al. 2001). Threats include habitat loss and fragmentation due to agricultural conversion (cropland and tame pasture), encroachment of woody vegetation, and urban development. For details on LBCU ecology, management, and conservation, refer to Dugger and Dugger (2002).
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Stephanie L. Jones et al.Monitoring Results for
Breeding American
Peregrine Falcons (<i>Falco
peregrinus anatum</i>), 2003https://digitalcommons.unl.edu/usfwspubs/515
https://digitalcommons.unl.edu/usfwspubs/515Thu, 03 Mar 2016 09:53:15 PST
In 2003, the U.S. Fish and Wildlife Service (Service) implemented the first of five nationwide monitoring efforts for American Peregrine Falcons (Falco peregrinus anatum) (Peregrine Falcons) as described in the Service’s post-delisting monitoring plan (USFWS 2003). More than 300 observers monitored 438 Peregrine Falcon territories across six monitoring regions. Monitoring in the Southwestern monitoring region fell short of the monitoring goal, where 36 of the targeted 96 territories were monitored; efforts are underway to implement full-scale monitoring in that region in 2006. The five other monitoring regions surveyed sufficient territories to meet the statistical criteria described in the post-delisting monitoring plan. Our estimates of territory occupancy, nest success, and productivity were above the target values that we set in the monitoring plan for those nesting parameters. Additional data collected by this effort documented that the total number of nesting pairs of Peregrine Falcons is estimated at 3,005. Additional data show that 92% of pairs nest on natural substrates in all regions except the Midwestern/ Northeastern region, where only 32% nest on natural substrates. Our estimates of the nesting parameters and the additional data from across the United States indicate that the Peregrine Falcon population is secure and vital. The next coordinated nationwide monitoring effort is scheduled for 2006 (USFWS 2003).
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Michael Green et al.Rocky Mountain Population of
Trumpeter Swanshttps://digitalcommons.unl.edu/usfwspubs/514
https://digitalcommons.unl.edu/usfwspubs/514Thu, 03 Mar 2016 09:52:57 PST
Trumpeter swans (Cygnus buccinator) are native only to North America. Although no historical estimates of their abundance are available, by 1900 they had been eliminated from most of their historical range in the U.S. and Canada. Through habitat conservation, protection from illegal shooting, supplemental winter feeding, and re-introduction and translocation efforts, trumpeter swans have increased from a few hundred birds to nearly 35,000. To facilitate monitoring and management, the U.S. Fish and Wildlife Service (FWS) and Canadian Wildlife Service (CWS) designated three populations: the Pacific Coast (PCP), the Rocky Mountain (RMP), and Interior (IP). The Rocky Mountain Population (RMP) increased from less than 200 in the early 1930s to 4,701 in February 2007. Even though distribution patterns have changed since the late 1980s, about 80% of the population (n=4,449/5,484 in winter 2006) continues to winter in the core Tri-state Area of southeast Idaho, southwest Montana, and northwest Wyoming. This restricted winter range distribution is still a priority concern for the RMP, although there has been a gradual shift to the southern half of the core tri-state area and sites further south since hazing and winter translocations began at Harriman State Park (HSP) and Red Rock Lakes National Wildlife Refuge (NWR) in 1990 (Shea and Drewien 1999). Coincident with summer releases of captive-raised swans in Wyoming (1994-2002) and at Bear Lake in Idaho (2001-2004), and winter translocations in Idaho (2001-2004), an increasing percentage of swans have wintered south of the core Tri-state Area in the Green, Salt, and Bear River drainages of Idaho and Wyoming. In the winter of 2007, 34% (n=351/1,024) of swans in Wyoming and 23% in Idaho (n=696/3,080) were south of the core area (data from U.S. Fish and Wildlife Service 2007). A small number of swans have been reported from Utah, Colorado, Nevada, Arizona, and California as well.
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TRUMPETER SWAN SURVEY
of the
ROCKY MOUNTAIN POPULATION
WINTER 2005https://digitalcommons.unl.edu/usfwspubs/513
https://digitalcommons.unl.edu/usfwspubs/513Thu, 03 Mar 2016 09:52:45 PST
Observers counted 5,361 swans (white birds and cygnets) in the Rocky Mountain Population of trumpeter swans during February 2005, an increase of 17% from the 4,584 counted in February 2004 and the second consecutive record-high count for the Mid-winter Survey. The numbers of white birds (4,206) and cygnets (1,155) increased 10% and 53%, respectively, from counts last year. In the tri-state area, increases in total swans occurred in Idaho (+20%) and Wyoming (+25%), but decreased slightly in Montana (-7%). The number of birds wintering in areas near restoration flocks was higher than counts in recent years, largely due to more complete survey coverage in the Summer Lake WMA this winter. However, counts at Malheur NWR remained near historic lows, and the count at Ruby Lake NWR was the lowest since 1995. Drought conditions persisted in much of the tri-state area, and reservoir levels in early February remained among the lowest recorded for that time of year. Generally, temperatures during winter 2004-05 were slightly warmer than average, with short periods of cool temperatures in December. Temperatures were colder than average in western Wyoming and southern Idaho during February, but warmer than average in Montana. Precipitation in primary winter areas was well below average from December 2004 through February 2005.
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James A. DubovskyTRUMPETER SWAN SURVEY
of the
ROCKY MOUNTAIN POPULATION
WINTER 2008https://digitalcommons.unl.edu/usfwspubs/512
https://digitalcommons.unl.edu/usfwspubs/512Thu, 03 Mar 2016 09:52:32 PST
Observers counted 4,637 swans (white birds and cygnets) in the Rocky Mountain Population of trumpeter swans during January and February 2008, which essentially was unchanged (-1%) from the 4,701 counted during winter 2007. The numbers of white birds (3,818) increased 4%, but the number of cygnets (808) decreased 12% from counts last year. However, these changes are somewhat biased due to a number of birds in Idaho not being classified as either white birds or cygnets in both 2007 (122 birds) and 2008 (11 birds). In the tri-state area, the number of total swans decreased in Montana (-21%) and Wyoming (-20%), but increased (+8%) in Idaho. The decrease in Wyoming was attributable primarily to a decrease in birds observed at Yellowstone National Park (-57%). The number of birds wintering in areas near restoration flocks was the highest since 1998. The numbers of birds near Summer Lake Wildlife Management Area (WMA) and at Ruby Lake National Wildlife Refuge (NWR) were essentially identical to those of last year, but the number of birds counted at Malheur NWR increased. Reservoir levels in early February were dramatically lower than during winter 2007, and cumulatively were 20% below the long-term average. Generally, temperatures in the tri-state area during winter 2007-08 were colder than average, and precipitation was near average or slightly above.
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James A. Dubovsky